EP2336018A1 - Sport device containing a polyurethane compound system - Google Patents

Abstract

Sports equipment, comprises a polyurethane composite system comprising a rigid polyurethane foam and a coating agent from a compact polyurethane or a compact polyurea. The rigid polyurethane foam is a porous three-dimensional reinforcing agent, which forms a network. The network surrounds at least 50% of the volume of the rigid polyurethane foam, or comprises at least two layers of a porous, at least two-dimensional reinforcing agent. An independent claim is also included for producing the sports equipment, preferably a water sports equipment or a racket sports equipment, comprising providing a rigid polyurethane foam comprising a porous three-dimensional reinforcing agent, which forms a network, where network surrounds at least 50% of the volume of the rigid polyurethane foam, or comprises at least two layers of a porous, at least two-dimensional reinforcing agent, and coating the rigid polyurethane foam with the compact polyurethane or the compact polyurea, where a coating agent for producing a compact polyurethane or a compact polyurea is subsequently sprayed to parts or the entire inner surface of a mold and reinforcing agent and the reaction mixture for producing a rigid polyurethane foam in to the mold is allowed to react.

Description

The present invention relates to a sports device comprising a polyurethane composite system comprising a rigid polyurethane foam and a coating agent of a compact polyurethane or a compact polyurea, wherein the polyurethane rigid foam contains a reinforcing agent. Furthermore, the present invention relates to a method for producing the sports equipment and the use of the polyurethane composite system in sports equipment.

In many areas, composites based on a rigid polyurethane foam coated with a coating material are known. The coating is usually carried out in such a way that by means of rigid polyurethane foam, a prefabricated housing is foamed or a rigid polyurethane foam is produced, which is then connected to a cover layer. In the first case, these are used, for example, as bumpers in automobiles or as coolers or refrigerator housings, in the second case, with a coating of painted metal sheets, used as facade cladding. A big advantage of these low-density composite materials is their low weight, combined with a certain mechanical stability. Another advantage is the individuality of the material. Thus, the desired object can be made individually from a block of rigid polyurethane foam and then provided with a coating.

A disadvantage of low-density foam materials are their low compressive strength, low impact strength and only moderate core stiffness and low bending strength. If a high rigidity and compressive strength and at the same time a low weight of the material is required, for example for sports equipment, such as surfboards, winter sports equipment, small sports boats or tennis rackets, the polyurethane rigid foams are stiffened by stiffening agents. These are, for example, parts made of wood or metal and resin-reinforced fiberglass mats. These reinforcing parts are for example inserted in milled depressions in rigid polyurethane foam or applied to the surface thereof. Surfboards are typically made by one "Stringer", a wooden board, usually balsa wood glued into a cut or milled recess in the core of the surfboard, stiffens. Although the use of the "stringer" largely prevents the surfboard from bending, such surfboards still tend to twist in the longitudinal axis.

To further improve the rigidity and to improve the compressive strength, the surface of the rigid polyurethane foams is coated with compact coating materials. These coatings may be inflexible, highly rigid materials, such as metal or polystyrene plates, or partially flexible materials, such as multiple layers of epoxy resin impregnated fiberglass mats. In order to obtain a surface with high surface quality, each layer of epoxy resin-impregnated glass fiber mats must be abraded after drying. After application of mostly 2 to 3 layers of glass fiber mats they are ground flat, painted, possibly get a design print and a clear coat finish, and possibly treads, handles and fasteners. This process is very time consuming and laborious, and the use of inserts and the coating of multiple layers of epoxy resin impregnated fiberglass mats partially obviates the advantage of the low weight of the composite. Furthermore, epoxy resin is relatively expensive.

Also known are coated polyurethane foam foams made of a rigid polyurethane foam containing a short fiber material as a reinforcing agent, and a polyurea coating. These composite systems are prepared by containing at least one component of the reaction mixture for producing the rigid polyurethane foam, the reinforcing agent before mixing or by spraying the reinforcing agent into a mold together with the reaction mixture. Such composites are for example in US 2002/0137871 or US 2008/299372 described. A disadvantage of these composites is that only small improvements in the mechanical properties, in particular the flexural strength, are obtained. Further, one is bound in the manufacture of the shape of the mold and thus no individual shape of the composite body is possible.

US 2008/0287017 A1 discloses a surfboard having carbon fibers applied externally instead of the "stringer" as reinforcement. The core of the surfboard remains unreinforced.

Object of the present invention was to provide a sports equipment, in particular a water sports equipment or a racquet sports equipment available, which has excellent rigidity, impact resistance and compressive strength at a lower total weight and is easy and inexpensive to produce. Another object was to provide a method that allows flexible variations of the final form / design of the sports equipment.

The object of the invention is achieved by a sports device based on a polyurethane composite system comprising a rigid polyurethane foam and a coating agent of a compact polyurethane or a compact polyurea, wherein the rigid polyurethane foam is a porous, three-dimensional reinforcing agent forming a network, the network at least 50% of the volume of rigid polyurethane foam or at least two layers of a porous, at least two-dimensional reinforcing agent. The layers are preferably distributed homogeneously in the foam. Homogeneously distributed in this context means that the maximum distance between two adjacent layers to each other or the upper layer of the top of the foam or the lower layer of the lower side of the foam from the minimum distance between two adjacent layers or the upper layer from the top or the bottom layer from the bottom by not more than a factor of 2, preferably not more than a factor of 1.5 different from each other.

According to the invention, the sports device is preferably a water sports device or a racquet sports device. A water sports device is a device which can be slid on or in the water. In particular, a water sports equipment is a surfboard, windsurfing board, kiteboard, wakeboard or water ski. Surfboards according to the invention are preferred.

A racquet sports equipment is in particular a tennis racket, badminton rackets, racquetball rackets, squash rackets or paddle sticks. According to the invention, tennis rackets are preferred.

The sports device according to the invention contains the polyurethane composite system, preferably it consists essentially of the polyurethane composite system. "Consists essentially of the polyurethane composite system" means in connection with the Sports device according to the invention, that the sports equipment up to design-related additions such as eyelets, coatings, treads and / or perforations, or as usual with racquet sports equipment, by a covering, coating or by adding a handle, otherwise from the polyurethane composite system. For example, this is understood to mean that in the water sports device, in particular in the surfboard, the displacement body consists essentially of the polyurethane composite system, except for coatings, grommets, holes and / or cutouts to supplement, for example, Finns and the racquet sports equipment, especially the tennis rackets on covering, coating and / or supplement of a handle made of the polyurethane composite system.

The reinforced rigid foam used in the polyurethane composite system preferably has a density-independent compressive strength of at least 5 * 10 ^-4 MPa * (L / g) ^1.6 , in particular at least 5.5 * 10 ^-4 MPa * (L / g) ^1.6 and preferred a density-independent pressure modulus of at least 8 * 10 ^-3 MPa * (L / g) ^1.7 , in particular at least 9.5 * 10 ^-3 MPa / (L / g) ^1.7 . The density-independent compressive strength was calculated according to compressive strength * (density) ^-1.6 and the density-independent compressive modulus of elasticity according to compressive modulus * (density) ^-1.7 . This means for a reinforced rigid foam used in the polyurethane composite system at a foam density of 45 g / L a preferred compressive strength of at least 0.2 MPa, more preferably at least 0.25 MPa and a preferred compressive modulus of at least 5 MPa, more preferably at least 6 MPa. Furthermore, at a density of 45 g / L, the rigid foam typically has a flexural strength of at least 0.4 MPa, preferably at least 0.5 MPa. The polyurethane composite system according to the invention has a surface hardness of typically at least 400 N, preferably at least 500 N, at a foam density of 45 g / L and a layer thickness of the coating material of 1 mm. The reinforced rigid polyurethane foam used according to the invention typically has a density of 30 g / L to 500 g / L, preferably 40 g / L to 400 g / L, particularly preferably 40 g / L to 300 g / L, in particular 40 g / L to 200 g / L on, or 40 g / L to 100 g / L, such as about 40 g / L to 60 g / L.

In the context of the present invention, the reinforcing agents are referred to as porous if the reaction mixture for producing the rigid polyurethane foam can penetrate into the reinforcing agent and penetrate and substantially completely wet it. This forms the Reinforcement means two-dimensional or three-dimensional networks in the rigid polyurethane foam of the polyurethane composite system. The network forming materials, such as fibers, nonwovens, mats, rovings or ribbons are preferably bonded together, for example by entanglements or links, for example between the mats. For the formation of three-dimensional networks, a plurality of two-dimensional reinforcing agents can be combined and / or three-dimensional reinforcing means such as fiber strands, which are optionally twisted or interlaced, such as fiber braids, preferably made of glass fibers, are used. The preferred porous three-dimensional reinforcing agent used is a three-dimensional, for example monolayer or multilayer, fiber web, preferably of glass fibers, for example a glass fiber scrim or multilayer glass filament scrim. The reinforcing means may for example consist of glass fibers, aramid fibers, carbon fibers or fibers made of plastic, preference is given to glass fibers. It is also possible that the reinforcing materials consist of a combination of these materials. For example, a three-dimensional reinforcing agent may consist of two glass fiber mats joined by polyamide fibers. Preferably, the reinforcing agent consists only of glass fibers. The two-dimensional reinforcing agent is preferably used in at least two layers. In order to achieve that the three-dimensional network encloses at least 50% of the volume of the rigid polyurethane foam, a three-dimensional reinforcing agent is preferably used.

Such two- or three-dimensional networks are obtained, for example, through the use of fibers, fibers or knits. Such two-dimensional reinforcing agents are preferably fiber mats, such as textile, glass fiber or carbon fiber mats or tapes, preferably glass fiber mats, for example Unifilo® U801 or U809 from Owens Corning Vetrotex. In this case, the porosity of the reinforcing material should be so pronounced that the reaction mixture for producing the rigid polyurethane foam is able to penetrate the reinforcing agent and to substantially completely wet its surface. The proportion of the reinforcing agent is preferably 5 to 40% by weight, more preferably 10 to 20% by weight, based on the total weight of the rigid polyurethane foam including reinforcing agent.

The rigid polyurethane foam of the polyurethane composite system used in sports equipment of the present invention, in one embodiment, includes a porous three-dimensional reinforcing agent forming a network. The network encloses at least 50% of the volume of the rigid polyurethane foam, preferably at least 60%, more preferably at least 75%, in particular at least 90%, for example at least 95%, of the volume of the rigid polyurethane foam or essentially comprises the volume of the rigid polyurethane foam. The volume of the rigid polyurethane foam is preferably understood to mean the space, in particular the contiguous space, which is filled by the rigid polyurethane foam. Typically, it is a single contiguous space.

Preferably, the rigid polyurethane foam of the sports equipment according to the invention is obtained by mixing (a) isocyanates, (b) compounds with isocyanate-reactive groups, (c) blowing agents containing water, (d) catalysts and optionally (e) other additives, such that a reaction mixture application, applying the reaction mixture to a reinforcing agent and curing the reaction mixture. For this purpose, the layers of the reinforcing agent are typically introduced and the polyurethane reaction mixture applied to these layers of the reinforcing agent. The reaction mixture substantially completely soaks through the reinforcing agent. The blowing reaction of the polyurethane reaction mixture homogeneously distributes the various layers of the two-dimensional or network of the three-dimensional reinforcing agent in the foam, i. by the blowing reaction of the polyurethane reaction mixture, the reinforcing agent substantially completely impregnated therefrom is inflated and stretched such that the network formed by the three-dimensional reinforcing agent encloses at least 50% of the volume of rigid polyurethane foam.

As isocyanates (a) it is possible to use all customary aliphatic, cycloaliphatic and preferably aromatic di- and / or polyisocyanates. These preferably have a viscosity of less than 600 mPas, particularly preferably less than 500 mPas and in particular less than 350 mPas, measured at 25 ° C. Toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI) and particularly preferably mixtures of diphenylmethane diisocyanate and polymeric diphenylmethane diisocyanate (PMDI) may be used as preferred isocyanates become. These particularly preferred isocyanates may be wholly or partially modified with uretdione, carbamate, isocyanurate, carbodiimide, allophanate and preferably urethane groups.

Furthermore, prepolymers and mixtures of the above-described isocyanates and prepolymers can be used as the isocyanate component. These prepolymers are prepared from the isocyanates described above and the polyethers, polyesters or both described below and usually have an NCO content of 14 to 32 wt .-%, preferably 22 to 30 wt .-%, on.

As compounds with isocyanate-reactive groups (b) it is possible to use all compounds which have at least two isocyanate-reactive groups, such as OH, SH, NH and CH-acid groups. Usually, polyetherols and / or polyesterols having preferably 2 to 8 isocyanate-reactive hydrogen atoms are used. The OH number of these compounds is usually in the range of 30 to 850 mg KOH / g, preferably in the range of 80 and 600 mg KOH / g.

The polyetherols are obtained by known processes, for example by anionic polymerization of alkylene oxides with the addition of at least one starter molecule which contains 2 to 8, preferably 2 to 6 reactive hydrogen atoms bound, in the presence of catalysts. Suitable catalysts are alkali metal hydroxides, such as sodium or potassium hydroxide or alkali metal alkoxides, such as sodium methylate, sodium or potassium ethylate or potassium isopropylate, or, in the case of cationic polymerization, Lewis acids, such as antimony pentachloride, boron trifluoride etherate or bleaching earth, as catalysts. Further, as catalysts and Doppelmetallcyanidverbindungen, so-called DMC catalysts can be used.

As alkylene oxides, preference is given to one or more compounds having 2 to 4 carbon atoms in the alkylene radical, such as tetrahydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide, in each case alone or in the form of mixtures, and preferably ethylene oxide and / or 1,2-propylene oxide used.

Examples of starter molecules are ethylene glycol, diethylene glycol, glycerol, trimethylolpropane, pentaerythritol, sugar derivatives, such as sucrose, hexitol derivatives, such as Sorbitol, methylamine, ethylamine, isopropylamine, butylamine, benzylamine, aniline, toluidine, toluenediamine, naphthylamine, ethylenediamine, diethylenetriamine, 4,4'-methylenedianiline, 1,3-propanediamine, 1,6-hexanediamine, ethanolamine, diethanolamine, triethanolamine and other dihydric or polyhydric alcohols or mono- or polyhydric amines.

The polyester alcohols used are usually by condensation of polyfunctional alcohols having 2 to 12 carbon atoms, such as ethylene glycol, diethylene glycol, butanediol, trimethylolpropane, glycerol or pentaerythritol, with polyfunctional carboxylic acids having 2 to 12 carbon atoms, for example succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid , Decanedicarboxylic acid, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, the isomers of naphthalenedicarboxylic acids or the anhydrides of said acids.

As further starting materials in the production of polyesters also hydrophobic substances can be used with. The hydrophobic substances are water-insoluble substances which contain a non-polar organic radical and have at least one reactive group selected from hydroxyl, carboxylic acid, carboxylic acid esters or mixtures thereof. The equivalent weight of the hydrophobic materials is preferably between 130 and 1000 g / mol. For example, there may be used fatty acids such as stearic acid, oleic acid, palmitic acid, lauric acid or linoleic acid, as well as fats and oils such as castor oil, corn oil, sunflower oil, soybean oil, coconut oil, olive oil or tall oil. If polyesters contain hydrophobic substances, the proportion of hydrophobic substances in the total monomer content of the polyester alcohol is preferably 1 to 30 mol%, particularly preferably 4 to 15 mol%.

The polyesterols used preferably have a functionality of 1.5 to 5, particularly preferably 1.8 to 3.5 and in particular from 1.9 to 2.2.

Further, the compound having isocyanate-reactive groups (b) preferably contains chain extenders and / or crosslinking agents. Suitable chain extenders and / or crosslinking agents are, in particular, difunctional or trifunctional amines and alcohols, in particular diols, triols or both, each having usually molecular weights of less than 350 g mol ^-1 , preferably from 60 to 300 g mol ^-1 , and in particular 60 to 250 g mol ^-1 used. This is called bifunctional Compounds of chain extenders and tri- or higher-functional compounds of crosslinkers. For example, suitable are aliphatic, cycloaliphatic and / or aromatic diols having 2 to 14, preferably 2 to 10 carbon atoms, such as ethylene glycol, 1,2-, 1,3-propanediol, 1,2-, 1,3-pentanediol, 1, 10-decanediol, 1,2-, 1,3-, 1,4-dihydroxycyclohexane, di- and triethylene glycol, di- and tripropylene glycol, 1,4-butanediol, 1,6-hexanediol and bis (2-hydroxyethyl) - hydroquinone, triols, such as 1,2,4-, 1,3,5-trihydroxycyclohexane, glycerol and trimethylolpropane, and low molecular weight hydroxyl-containing polyalkylene oxides based on ethylene and / or 1,2-propylene oxide and the abovementioned diols and / or triols as starter molecules. In this case, the compound containing isocyanate-reactive groups (b) preferably contains a polyetherol (b1) having a functionality of 4 or greater and a viscosity at 25 ° C of 10,000 mPas or less and a polyetherol (b2) having a functionality of 3.5 or smaller, preferably 3 or smaller and a viscosity at 25 ° C of 600 mPas or less, preferably 500 mPas or less. Particularly preferably, the compound containing isocyanate-reactive groups (b) contains, in addition to the polyetherols (b1) and (b2), a polyesterol (b3) having a viscosity at 25 ° C. of 2,000 mPas or less and optionally at least one chain extender (b4) and / or a crosslinker (b5).

In each case individual compounds or mixtures can be used as components (b1) to (b5), each of the compounds used falling within the definition of (b1) to (b5).

The chain extender (b4) may be single compounds or mixtures. The chain extender (b4) preferably contains dipropylene glycol, tripropylene glycol and / or 2,3-butanediol alone or, if appropriate, in mixtures with one another or with further chain extenders.

In a further embodiment, the compounds containing isocyanate-reactive groups (b) in addition to the polyetherol (b1), the polyetherol (b2), the polyesterol (b3) and the chain extender (b4) contain a crosslinking agent (b5). The crosslinking agent used is preferably 1,2,4-, 1,3,5-trihydroxycyclohexane, glycerol and / or trimethylolpropane. Preferably, glycerol is used as crosslinking agent.

The proportion of component (b1) is preferably 25 to 70 wt .-%, more preferably 25 to 55 wt .-% and in particular 30 to 50 wt .-%, based on the total weight of component (b).

The proportion of component (b2) is preferably 10 to 40 wt .-%, particularly preferably 15 to 35 wt .-%, based on the total weight of component (b).

The proportion of component (b3) is preferably 15 to 50 wt .-%, particularly preferably 20 to 40 wt .-%, based on the total weight of component (b).

The proportion of chain extender (b4) in component (b) is preferably from 1 to 30% by weight, particularly preferably from 5 to 20% by weight, based on the total weight of component (b).

The proportion of component (b5) in component (b) is preferably 0 to 10 wt .-%, particularly preferably 1 to 5 wt .-%, based on the total weight of component (b).

The proportion of the polyetherols (b1), (b2), (b3), (b4) and optionally (b5) on the compound with isocyanate-reactive groups (b) is preferably at least 80% by weight, particularly preferably at least 90% by weight. -% and in particular 100 wt .-%, based on the total weight of the compound with isocyanate-reactive groups (b).

Preferably, the total functionality of component (b) is greater than 2.5, more preferably greater than 2.6 and especially greater than 2.75. The mean OH number of component (b) is preferably greater than 300 mg KOH / g, particularly preferably between 350 and 1000 mg KOH / g and in particular between 400 and 600 mg KOH / g.

If isocyanate prepolymers are used as isocyanates (a), the content of compounds with isocyanate-reactive groups (b), including the compounds used for the preparation of the isocyanate prepolymers, is calculated with isocyanate-reactive groups (b).

As blowing agent (c) propellant, containing water, is used. In this case, water can be used alone or in combination with other blowing agents. The content of water in the blowing agent (c) is preferably greater than 40 wt .-%, more preferably greater than 60 wt .-% and most preferably greater than 80 wt .-%, based on the total weight of the blowing agent (c). In particular, water is used as the substantially sole blowing agent. If further blowing agents are used in addition to water, it is possible to use, for example, chlorofluorocarbons, fluorohydrocarbons, hydrocarbons, acids and / or liquid or dissolved carbon dioxide. Propellant (c) preferably contains less than 50% by weight, more preferably less than 20% by weight, particularly preferably less than 10% by weight and in particular 0% by weight, based on the total weight of propellant (c), Chlorofluorocarbons, fluorohydrocarbons and / or hydrocarbons. In a further embodiment, a mixture of water and formic acid and / or carbon dioxide can be used as blowing agent (c). In order to more easily disperse the blowing agent in the polyol component, the blowing agent (c) may be mixed with polar compounds such as dipropylene glycol.

The blowing agents (c) are usually used in such an amount that the density of the rigid polyurethane foam produced by the reaction of the components (a) to (e) including reinforcing agent is in the range of 30-500, preferably 40-400, more preferably 40 to 300, in particular 40 to 200 g / L, or 40 g / L to 100 g / L, such as about 40 g / L to 60 g / L.

As catalysts (d) it is possible to use all compounds which accelerate the isocyanate-water reaction or the isocyanate-polyol reaction. Such compounds are known and described, for example, in "Kunststoffhandbuch, Volume 7, Polyurethanes", Carl Hanser Verlag, 3rd edition 1993, Chapter 3.4.1. These include amine-based catalysts and catalysts based on organic metal compounds.

As catalysts based on organic metal compounds, for example, organic tin compounds, such as tin (11) salts of organic carboxylic acids, such as tin (11) acetate, tin (11) octoate, tin (11) ethyl hexoate and tin (II) laurate and the dialkyltin (IV) salts of organic carboxylic acids, such as dibutyltin diacetate, Dibutyltin dilaurate, dibutyltin maleate and dioctyltin diacetate, and bismuth carboxylates such as bismuth (111) neodecanoate, bismuth 2-ethylhexanoate and bismuth octanoate or alkali metal salts of carboxylic acids such as potassium acetate or potassium formate can be used.

As catalyst (d) it is preferred to use a mixture containing at least one tertiary amine. These tertiary amines are usually compounds which may also carry isocyanate-reactive groups, such as OH, NH or NH ₂ groups. Some of the most commonly used catalysts are bis (2-dimethylaminoethyl) ether, N, N, N, N, N-pentamethyldiethylenetriamine, N, N, N-triethylaminoethoxyethanol, dimethylcyclohexylamine, dimethylbenzylamine, triethylamine, triethylenediamine, pentamethyldipropylenetriamine , Dimethylethanolamine, N-methylimidazole, N-ethylimidazole, tetramethylhexamethylenediamine, tris (dimethylaminopropyl) hexahydrotriazine, dimethylaminopropylamine, N-ethylmorpholine, diazabicycloundecene and diazabicyclononene. Preferably, as catalysts (d) mixtures are used which contain at least two different tertiary amines. The catalyst mixture (d) particularly preferably contains dimethylcyclohexylamine (d1) and bis (2-dimethylaminoethyl) ether (d2) or dimethylcyclohexylamine (d1) and N, N, N, N, N-pentamethyldiethylenetriamine (d3). The ratio of dimethylcyclohexylamine (d1) and bis (2-dimethyl-aminoethyl) ether (d2) and / or the ratio of dimethylcyclohexylamine (d1) and N, N, N, N, N-pentamethyldiethylenetriamine (d3) is preferably 0, 25 to 4 to 1, more preferably 0.5 to 2 to 1. In particular, when using the polyurethane composite systems of the invention in enclosed spaces, for example in the interior of transport, alternative catalysts can be used, whereby emissions are reduced. Such catalysts are, for example, incorporable catalysts. Also can be completely dispensed with catalysts.

As reinforcing agent, all the above-mentioned reinforcing agents can be used.

As further additives (e) flame retardants, plasticizers, foam stabilizers, other fillers and other additives, such as antioxidants can be used.

As flame retardants, the flame retardants known from the prior art can generally be used. Suitable flame retardants are, for example, brominated ethers (Ixol B 251), brominated alcohols, such as dibromoneopentyl alcohol, Tribromoneopentyl alcohol and PHT-4-diol, as well as chlorinated phosphates, such as, for example, tris (2-chloroethyl) phosphate, tris (2-chloroisopropyl) phosphate (TCPP), tris (1,3-dichloroisopropyl) phosphate, tris (2, 3-dibromopropyl) phosphate and tetrakis (2-chloroethyl) ethylenediphosphate, or mixtures thereof.

Besides the abovementioned halogen-substituted phosphates, it is also possible to use inorganic flame retardants, such as red phosphorus, red phosphorus-containing compositions, expandable graphite, alumina hydrate, antimony trioxide, arsenic oxide, ammonium polyphosphate and calcium sulfate or cyanuric acid derivatives, such as melamine, or mixtures of at least two flame retardants, such as ammonium polyphosphates and melamine, and optionally starch, for flameproofing the rigid polyurethane foams produced according to the invention.

Diethyl ethane phosphonate (DEEP), triethyl phosphate (TEP), dimethyl propyl phosphonate (DMPP), diphenyl cresyl phosphate (DPK) and others can be used as other liquid halogen-free flame retardants.

The flame retardants are used in the context of the present invention preferably in an amount of 0 to 25 wt .-%, in particular 5 to 15 wt .-% based on the total weight of components (b) to (e).

Foam stabilizers are substances which promote the formation of a regular cell structure during foaming. For example: silicone-containing foam stabilizers, such as siloxane-oxalkylene copolymers and other organopolysiloxanes. Further alkoxylation of fatty alcohols, oxo alcohols, fatty amines, alkylphenols, dialkylphenols, alkylcresols, alkylresorcinol, naphthol, alkylnaphthol, naphthylamine, aniline, alkylaniline, toluidine, bisphenol A, alkylated bisphenol A, polyvinyl alcohol, and further alkoxylation of condensation products of formaldehyde and alkylphenols, formaldehyde and Dialkylphenols, formaldehyde and alkyl cresols, formaldehyde and alkylresorcinol, formaldehyde and aniline, formaldehyde and toluidine, formaldehyde and naphthol, formaldehyde and alkylnaphthol and formaldehyde and bisphenol A or mixtures of two or more of these foam stabilizers.

Foam stabilizers are preferably used in an amount of 0.5 to 4 wt .-%, particularly preferably 1 to 3 wt .-%, based on the total weight of components (b) to (e).

Further fillers, in particular reinforcing fillers, are the known conventional organic and inorganic fillers, reinforcing agents, etc. Specific examples are: inorganic fillers such as silicate minerals, for example phyllosilicates such as antigorite, serpentine, hornblende, amphibole, chrysotile, talc; Metal oxides such as kaolin, aluminas, titanium oxides and iron oxides, metal salts such as chalk, barite and inorganic pigments such as cadmium sulfide, zinc sulfide and glass and others. Preference is given to using kaolin (China Clay), aluminum silicate and coprecipitates of barium sulfate and aluminum silicate, as well as natural and synthetic fibrous minerals such as wollastonite, metal fibers and in particular glass fibers of various lengths, which may optionally be sized. It is also possible to use glass microbubbles. Examples of suitable organic fillers are: carbon, melamine, rosin, cyclopentadienyl resins and graft polymers, as well as cellulose fibers, polyamide, polyacrylonitrile, polyurethane, polyester fibers based on aromatic and / or aliphatic dicarboxylic acid esters and carbon fibers.

The further, in particular inorganic and organic fillers can be used individually or as mixtures and are advantageously added to the reaction mixture in amounts of 0.5 to 30% by weight, preferably 1 to 15% by weight, based on the weight of components (a) to (e), added.

The present invention also relates to a method for producing a sports device, in particular a sports device as described above, wherein a rigid polyurethane foam containing a porous three-dimensional reinforcing agent forms a network, wherein the network encloses at least 50% of the volume of rigid polyurethane foam or at least one layer a porous, at least two-dimensional reinforcing agent is presented and coated with a compact polyurethane or a compact polyurea. Preferably, the rigid polyurethane foam is prepared by presenting the reinforcing agent, in particular a reinforcing agent as stated above, in one suitable form, for example, the surface of the desired sports equipment, preferably a tennis racket or surfboard, simulates addition of a reaction mixture, in particular a reaction mixture for producing the rigid polyurethane foam as defined above, and curing. Subsequently, the rigid polyurethane foam is preferably coated by spraying a reaction mixture for producing a compact polyurethane or a compact polyurea, in particular as described below, on the rigid polyurethane foam.

Preferably, the preparation of the rigid polyurethane foam takes place continuously on a belt or discontinuously in a mold as a block foam. For this purpose, components (b) to (d) and optionally (e) are preferably mixed to form a polyol component. These are then preferably mixed in a low pressure mixing device, a high pressure mixing device at a reduced pressure of less than 100 bar or a high pressure machine with the isocyanate component (a). Alternatively, the components (a) to (d) and optionally (e) can also be added individually to the mixing device. Subsequently, the reaction mixture thus obtained is applied to the reinforcing agent, preferably to the glass fiber mats or Glasfaserzopfgelege, which are preferably unrolled by several drums continuously on the tape or presented on the bottom of a mold, and optionally form there a corresponding number of layers. Subsequently, the resulting foam is preferably cured on the belt or in the mold to the extent that it can be cut into pieces without damage. This may be at room temperature (20 ° C) or at elevated temperatures, preferably from about 60 ° C to about 120 ° C, more preferably from about 70 ° C to about 90 ° C, for example when passing through an oven in the case of continuous production or through the Use of heated molds in the case of discontinuous production, carried out. Preferably, racquet sports equipment is cured at room temperature and water sports equipment at elevated temperature. The resulting foam pieces are then preferably stored further in order to obtain the full mechanical strength. The number of glass fiber mats used is freely selectable and depends on the desired glass fiber content in the foam and on the set foaming height over which the mats distribute homogeneously. For a foam height of 20-25 cm, for example, 3 to 10 mat layers of a mat density of about 450 g / m ^{2 are} preferred, in particular 5-8 mat layers.

Isocyanates (a) and compounds with isocyanate-reactive groups (b), blowing agents containing water (c), catalysts (d) and optionally further additives (e) are preferably reacted in amounts such that the isocyanate index in the range of 100 to 400, preferably 100-200, more preferably 100-150.

For the purposes of the present invention, isocyanate index is understood to mean the stoichiometric ratio of isocyanate groups to isocyanate-reactive groups multiplied by 100. Isocyanate-reactive groups are understood to mean all isocyanate-reactive groups contained in the reaction mixture, including chemical blowing agents, but not the isocyanate group itself.

It is particularly advantageous that the reaction mixtures for the production of rigid polyurethane foam as described above penetrate quickly into the reinforcing agent and thereby a uniform and space-filling as possible distribution of the reinforcing agent is obtained in the resulting rigid polyurethane foam. Also advantageous is the long start time of the reaction mixtures for the preparation of the rigid polyurethane foam as described above with a short reaction time. A further advantage is that the reaction mixtures for producing the rigid polyurethane foam as described above have a low viscosity and good flow behavior in order to fill large-area shapes or complex volumes right into the corners.

Reinforced and in particular coated rigid polyurethane foams according to the invention are mechanically stable, have a low thermal conductivity, exhibit excellent foaming properties, for example without holes and cracks, have good mechanical properties, such as pressure and impact strengths and an excellent pressure modulus, and have a uniform distribution of Layers of reinforcing agents on. Also, the sports equipment according to the invention show excellent UV resistance. The compressive strength and the compressive modulus of elasticity are measured both vertically and parallel to the foaming direction (in the x / y and z directions) in accordance with DIN 53421 / DIN EN ISO 604. The spatially averaged compressive strength and the compressive modulus of elasticity can be calculated according to (x * y * z) ^1/3 . The flexural strength is determined on specimens of 120 mm x 25 mm x 20 mm according to DIN 53423 at 25 ° C; the flexural strength of the Foam plane perpendicular to the foaming direction. The rigid polyurethane foam can be produced as a block and be cut or milled from the block foam body for the specific applications. In particular, more than one foam body can be obtained from a larger foam block. Thus, arbitrarily complex foam body shapes are easily possible as well as an individual production of small series or individual pieces of the sports equipment according to the invention possible

The rigid polyurethane foam is coated with a coating agent to produce a compact polyurethane, a compact polyurea or a polyurethane-polyurea hybrid system. In this case, any reaction product obtained by reaction of at least one compound having at least two isocyanate groups and a compound having at least two isocyanate-reactive groups and being substantially free of gas inclusions can be used in the coating composition as a compact polyurethane or as a compact polyurea. Preferably, the density of a compact polyurethane or a compact polyurea is greater than 0.8 g / cm ³ , particularly preferably greater than 0.9 g / cm ³ and in particular greater than 1.0 g / cm ³ . The term "polyurethane" refers to compounds which are obtainable when the reactive groups of the compound having at least two isocyanate-reactive groups are predominantly hydroxyl groups, and polyurea means compounds which are obtainable when the reactive groups of the compound are at least two opposite The amines are frequently reacted together with further auxiliaries and additives in the form of an amine component with the isocyanate.Preferably, the coating composition is a compact polyurea which is obtained by mixing compounds having at least two isocyanate groups with compounds is obtainable with at least two primary or secondary amines.

The coating of the rigid polyurethane foam preferably takes place by casting or spraying, particularly preferably by the spraying method, in which the rigid polyurethane foam is sprayed with the coating agent to produce the coating. Optionally, the polyurethane composite system can also be prepared in a mold. For this purpose, the inner wall of the mold is wholly or partially sprayed with the reaction mixture for the preparation of the coating and then the reinforcing agent and the reaction mixture for the preparation of the Polyurethane foam in the mold and allowed to react. The present invention thus also relates to a method for producing a sports equipment, in particular a sports equipment as stated above, in which the coating composition for producing a compact polyurethane or a compact polyurea is sprayed onto parts or the entire inner surface of a mold and then the reinforcing agent in the Form is submitted and the reaction mixture for the production of rigid polyurethane foam, in particular a reaction mixture as defined above, is added, and the foam is cured, in particular at room temperature or elevated temperatures as stated above. According to the invention, all known polyurethane or polyurea spray systems can be used. Such are known, for example, from Becker / Braun, Kunststoffhandbuch no.7, Polyurethanes, Chap. 10. DE102004022683 describes in detail polyurea spray systems. Preferably, compact polyureas are used for coating the rigid polyurethane foam.

For the preparation of compact polyurethane materials or polyureas, it is possible to use, for example, all isocyanates described under (a) as compounds having at least two isocyanate groups. Preference is given to using prepolymers based on an isomer or isomer mixture of diphenylmethane diisocyanate (MDI) and polyetherols, for example polypropylene glycols, as compounds having at least two isocyanate groups. The preparation of these isocyanate prepolymers is carried out by reacting in particular hydroxyl, furthermore also amine-terminated polyethylene or polypropylene oxides with the polyisocyanate. Preferably, the prepolymers used have an isocyanate content of 10-25 weight percent, more preferably 15-20 weight percent and a viscosity at 25 ° C of at most 2000 mPas, in particular between 300-1000 mPas.

The amine component is usually a mixture of primary aliphatic polyetheramines and usually aromatic amine chain extenders.

The main constituent of the amine component of a polyurea formulation is a mixture of polyetheramines, ie of amine-terminated di- or higher-functional polyethylene or polypropylene oxides with molecular weights of between 200 and 5000 g mol ^-1 . The aliphatic amines react faster than the aromatic ones Components of the chain extenders and serve primarily to build up the soft phase of the polyurea spray elastomers.

The chain extender commonly used in the polyurea formulation is diethylenetoluenediamine (DETDA). As a more unreactive component than aliphatic amines, DETDA determines the curing behavior of the system. To synthesize light-stable polyureas, aliphatic chain extenders are also used. The mostly aromatic chain extenders are predominantly incorporated into the hard phase of the polyurea spray elastomers. Furthermore, the polyurea formulation may contain further additives and additives as described above in the description of component (e), in particular the flame retardants described and defoaming agents and / or water-absorbing additives such as zeolites.

In a further embodiment of the sports device according to the invention, the coating may contain short fibers of a length of up to 2 cm, preferably about 0.6-2 cm. The fibers are usually stored separately and sprayed simultaneously with the coating agent or, alternatively, previously suspended in one or more components of the coating composition.

The coating is usually carried out to at least 30%, preferably at least 50%, particularly preferably at least 80% and in particular to 100% of the surface of the rigid polyurethane foam. With particular preference, all visible surfaces of the sports equipment according to the invention comprising the polyurethane composite system are coated, in the case of water sports equipment, in particular, all surfaces of the apparatus coming into contact with water.

After coating with the compact polyurethane or polyurea, the polyurethane composite system can be further coated, for example, with decorative coatings. For example, a decorative coat can be made. Furthermore, a complete or partial coating with a functional coating, for example an anti-slip coating, can also be carried out. Finally, typical additions and additions to the sports equipment, such as straps, holes, etc., in water sports equipment or clothing or mounting the handle on racquet sports equipment done.

Sports equipment according to the invention comprising the polyurethane composite system, in addition to a low weight on an excellent compressive strength, flexural strength, rigidity, impact resistance and surface quality. Further, they have excellent heat insulating properties and UV resistance. The polyurethane composite systems can be used, for example, in the production of sports equipment, in particular water sports equipment, such as surfboards, windsurfing boards, kite boards, wakeboards and water skis or racquet sports equipment, such as tennis rackets, badminton rackets, racquetball rackets, squash rackets and Paddleschlägern. In particular, surfboards (surfboards), windsurfing boards and kite boards (wind kite boards), which have a low material density and thus high buoyancy in the water and at the same time a high overall hardness, surface hardness, stiffness, impact resistance and bending strength can be produced with the polyurethane composite system.

The invention thus also relates to the use of a polyurethane composite system as described above containing a rigid polyurethane foam and a coating agent of a compact polyurethane or a compact polyurea, the rigid polyurethane foam containing a porous three-dimensional reinforcing agent forming a network, the network being at least 50% of the volume polyurethane rigid foam or at least two layers of a porous, at least two-dimensional reinforcing agent, in a sports equipment, in particular a water sports equipment, such as a surfboard, windsurfing board, kiteboard, wakeboard or water ski, or a racquet sports equipment, such as a tennis racket, badminton rackets, racquetball racquets, squash rackets or Paddleschläger ,

By way of examples, the advantages of the invention will be explained:

General instruction for the production of polyurethane composite systems, as they can be used in the sports equipment according to the invention:

To prepare the rigid foam 1, the polyurethane composite system 2 and the comparative example V1, the polyols used were stirred according to Table 1 with catalysts, stabilizer and blowing agent, then with the isocyanate mixed and the reaction mixture poured into a box with a base of 225 mm x 225 mm and foamed there. To prepare the reinforced rigid foams, the reaction mixture was placed in the same box, but now containing several layers of glass fiber mats type Unifilo U809-450. The reaction mixture penetrated into the mats and with the foam rising in the box, the mats swelled and spread homogeneously over the entire foam height. The blowing agent was used to set a constant foam bulk density of 45 g / l. The coating of the rigid foam with a 1 mm thick layer was carried out using the polyurea spray system Coating 1 from Table 2.

Compressive strength and compressive modulus of elasticity were measured parallel to the foaming direction in accordance with DIN 53421 at 25 ° C. The surface hardness was measured with a Tiratest 2602 instrument with a spherical cap with a diameter of 20mm at 25 ° C. The required force is measured to press the calotte 10 mm into the test specimen parallel to the foaming direction. Table 1 example 1
(Comparison) 2 V1 V2 V3 Polyol 1 30 30 30 30 30 Polyol 2 20 20 20 20 20 Polyol 3 30 30 30 30 30 dipropylene 18 18 18 18 18 foam stabilizer 2 2 2 2 2 water 1.8 1.8 1.8 1.8 1.8 formic acid 1.8 1.8 1.8 1.8 1.8 dimethylcyclohexylamine 0.3 0.3 0.3 0.3 0.3 Weight fraction glass fiber mats 10% 10% 0% 0% 0% Weight fraction short fibers (5cm) 0% 0% 0% 10% 10% isocyanate 172 172 172 172 172 Coating with coating 1 No Yes No No Yes Compressive strength [MPa] 0.27 0.32 0.22 nb nb Pressure modulus [MPa] 8.9 9.1 5.0 nb nb Surface hardness [N] 290 570 170 200 500 Bending strength [MPa] 0.56 nb nb nb 0.3 Polyetheramine, MW 2000 60 Polyetheramine, MW 400 20 diethylenetoluenediamine 20 Prepolymer MDI based, NCO content 15% 112

• Polyol 1: zuckerbasiertes Polyetherol, OH-Zahl = 500 mg KOH/g, Viskosität = 8000 mPas
• Polyol 2: Glycerinbasiertes Polyetherol, OH-Zahl = 400 mg KOH/g, Viskosität = 350 mPas
• Polyol 3: Phthalsäureanhydrid/Diethylenglykol-basiertes Polyesterol, OH-Zahl = 300 mg KOH/g, Viskosität = 1000 mPas
• Isocyanat: polymeres Methylendiphenyldiisocyanat (PMDI), Viskosität = 200 mPas
• die Viskositätsangaben beziehen sich jeweils auf die Viskosität bei 25 °C.
• Stabilisator: Silikonhaltiger Schaumstabilisator der Evonik Goldschmidt GmbH

The following starting materials were used:

• Polyol 1: sugar-based polyetherol, OH number = 500 mg KOH / g, viscosity = 8000 mPas
• Polyol 2: Glycerol-based polyetherol, OH number = 400 mg KOH / g, viscosity = 350 mPas
• Polyol 3: phthalic anhydride / diethylene glycol-based polyesterol, OH number = 300 mg KOH / g, viscosity = 1000 mPas
• Isocyanate: polymeric methylene diphenyl diisocyanate (PMDI), viscosity = 200 mPas
• the viscosity data in each case refer to the viscosity at 25 ° C.
• Stabilizer: Silicone-containing foam stabilizer from Evonik Goldschmidt GmbH

Table 1 shows that the hard polyurethane composite systems obtained have high compressive strengths, in particular surface hardness and high pressure moduli.

Example 1: Tennis rackets

To produce a tennis racket according to the invention, the metal mold (negative form of the racket) is coated in the first step with a layer thickness of about 1 to 2 mm of the glass-fiber-reinforced polyurea. For this purpose, a unidirectional glass filament fabric with a weight of 425 g / m ² mittles a bonding agent (eg, soft resin) are fixed in both halves of the metal mold and then impregnated with the polyurea by brushing or spraying. The polyurea cures in accordance with the setting in about 30 seconds. Then a Glasfaserzopfgelege is inserted into a half of the metal mold and over poured the reaction mixture for the production of rigid polyurethane foam. Then the other half of the metal mold is placed, the mold tightly closed and heated to about 80 ° C for 5 minutes. The resulting racquet has a weight of 230-360 grams depending on geometry and is comparable in frame rigidity and playability to a conventionally constructed racquet. The manufacturing cost of the construction according to the invention is about 60% of the conventional production method.

Example 2: Surfboard

To produce a surfboard according to the invention, in the first step in a conventional blank mold for surfboards made of the reinforced polyurethane foam, the foam preform, which in English so-called "blank" produced. For this purpose, a cut to the surfboard geometry multilayer Glasfilamentgelege is inserted into the mold and with the reaction mixture for the production of the polyurethane foam, which is set to a target density of rigid polyurethane foam of about 50 kg / m ³ , poured over. The reaction mixture in this case is a room temperature curing system. If appropriate, a so-called stringer (wood reinforcement in the axial direction) can additionally be glued in the preform. The foam preform is now milled to the desired shape using a CNC milling machine, details are added by hand if necessary. The now finished "blank" is now coated with the glass fiber reinforced polyurea.

For this purpose, the polyurea composite is applied only in a spray process with two nozzles by sprayed from a nozzle a long glass fiber with a length of about 0.6-2 cm on the "blank" and at the same time from the second nozzle of the polyurea is sprayed on the "blank" a finished composite is formed, which cures due to the system within a few seconds. Subsequently, another layer is sprayed with the polyurea to obtain a smooth and homogeneous surface structure.

The surfboard produced according to the invention has a significantly improved impact strength at the same density and improved mechanical properties in contrast to a conventional polyester laminated surfboard. The manufacturing cost of the inventive construction amount to about 60% of the conventional production method.

Claims (15)

A sports device comprising a polyurethane composite system containing a rigid polyurethane foam and a coating agent of a compact polyurethane or a compact polyurea, wherein the rigid polyurethane foam is a porous three-dimensional reinforcing agent forming a network, wherein the network encloses at least 50% of the volume of rigid polyurethane foam, or at least two layers a porous, at least two-dimensional reinforcing agent. Sports device according to claim 1, wherein it is a water sports device, in particular a surfboard, or a racquet sports equipment, in particular a tennis racket acts. Sports device according to claim 1 or 2, characterized in that the reinforcing means comprises glass fiber mats. Sports device according to one of claims 1 to 3, characterized in that the layers of the planar reinforcing agent are homogeneously distributed in the rigid polyurethane foam. Sports device according to one of claims 1 to 4, characterized in that the rigid polyurethane foam can be produced by mixing a) polyisocyanates b) compounds with isocyanate-reactive groups c) propellants containing water, d) a catalyst mixture containing tertiary amines and optionally e) other additives, to obtain a reaction mixture, applying the reaction mixture to a reinforcing agent and curing the reaction mixture. Sports device according to claim 5, characterized in that the compounds with isocyanate-reactive groups (b) a polyetherol (b1) having a functionality of 4 or greater and a viscosity at 25 ° C of 10,000 mPas or less and a polyetherol (b2) with a functionality of 3.5 or less and a viscosity at 25 ° C of 600 mPas or less. Sports device according to claim 6, characterized in that the compounds with isocyanate-reactive groups (b) in addition to the polyetherol (b1) and the polyetherol (b2) a polyesterol (b3) having a viscosity at 25 ° C of 2000 mPas or less, and optionally contain at least one chain extender (b4) and / or a crosslinker (b5). Sports device according to one of claims 1 to 7, characterized in that the polyurethane rigid foam contains as isocyanate component PMDI. Sports device according to one of claims 1 to 8, characterized in that the Poiyurethanhartschaumstoff has a density of 30 g / L to 500 g / L. Sports device according to one of claims 1 to 9, characterized in that the polyurethane hard foam has a density-independent compressive strength of at least 5 * 10 ^-4 MPa * (L / g) ^1.6 , preferably at least 5.5 * 10 ^-4 MPa * (L / g) ^1.6 . Sports device according to one of claims 1 to 9, characterized in that the rigid polyurethane foam has a density-independent pressure modulus of at least 8 * 10 ^-3 MPa * (L / g) ^1.7 , preferably at least 9.5 * 10 ^-3 MPa * (L / g) ^1.7 . Method for producing a sports device, in particular a water sports device or racquet sports device, characterized in that a rigid polyurethane foam containing a porous three-dimensional reinforcing agent forming a network, the network enclosing at least 50% of the volume of rigid polyurethane foam or at least one layer of a porous, at least two-dimensional reinforcing agent, and the polyurethane rigid foam coated with a compact polyurethane or a compact polyurea. A method according to claim 12, characterized in that the polyurethane rigid foam containing a porous three-dimensional reinforcing agent forming a network, the network enclosing at least 50% of the volume of rigid polyurethane foam or at least one layer of a porous, at least two-dimensional reinforcing agent by presenting the reinforcing agent in one Mold, adding a reaction mixture as defined in any one of claims 5 to 8, and curing, and coating the polyurethane rigid foam by spraying a coating agent to produce a compact polyurethane or a compact polyurea on the rigid polyurethane foam. A process for producing a sports equipment, in particular a water sports equipment or racquet sports equipment, characterized in that spraying a coating agent for producing a compact polyurethane or a compact polyurea on parts or the entire inner surface of a mold and then a reinforcing agent and a reaction mixture for producing a rigid polyurethane foam in gives form and lets it react. Use of a polyurethane composite system comprising a rigid polyurethane foam and a coating agent of a compact polyurethane or a compact polyurea, wherein the rigid polyurethane foam contains a porous three-dimensional reinforcing agent forming a network, wherein the network encloses at least 50% of the volume of rigid polyurethane foam or at least two layers of a porous , at least two-dimensional reinforcing means, in a sports equipment, preferably a water sports equipment, in particular a surfboard or a racquet sports equipment, in particular a tennis racket.